Obiteljska zbirka Dodgsonovih, kat.br. F/17/1. "Cut Pages in Diary". (Za izvještaj o pronalasku papira, vidjeti The Times Literary Supplement, 3. svibnja 1996.)
Carroll, Lewis, "What the Tortoise Said to Achilles", Mind n.s. 4 (1895), 278–280; rpt. in Mind 104 (1995), 691–693. Simon Blackburn, "Practical Tortoise Raising", Mind 104 (1995), 695 ff.[1]